15-30 hp phase converter, 2 in 1 ?

Found this ebay auction... Says the converter is a 15 or 30 hp converter as a 2 in 1. Says it runs 15hp, then flip a switch and get 30hp from a bank of capacitors, etc.

Here is the auction...

http://cgi.ebay.com/15-HP-30-HP-ROT...ryZ41952QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

is this a good deal? I have read all the threads i can without my brain melting, including the sticky at the top of the page. I have ZERO electrical experience. Is it possible for me to really build my own, and have it work, for enough savings to not go with a factory built one?

My lathe has a 10 hp motor, so how large of a converter do i need, if planning to do a bridgeport mill as well at a later date?

Any help is appreciated, thanks a lot!

It is a two-idler RPC with a single, unified control.

The same could be done with a shop-made RPC system, and as long as the smallest idler was used to start any remaining larger idlers, you could configure an RPC system with two, three, four, or more idlers, and there would only be one starting means, that which is on the smallest idler.

The controller for any subsequent idlers could be as simple as a fusible safety switch which placed that idler across the three-phase bus, but a properly designed, and interlocked magnetic motor starter would be my choice.

"fusible safety switch which placed that idler across the three-phase bus, but a properly designed, and interlocked magnetic motor starter would be my choice."

ok here's where i feel retarded... i don't know what any of this means, there fore i am afraid to mess with this stuff since it's such high voltage.

I am looking for an instruction manual that says. "First, go buy all of these part numbers from these companies. Next, build your boxes, wiring and placing everything so that it looks just like these photos with callouts of the part numbers. (photos, not electric schematics that look like Mandarin Chinese characters to me). Next source a motor that is rated for your horsepower needs based on the chart here, etc."

This doesn't exist, and i don't know enuf about electrical crap to begin to build it using the schematics and plans in the sticky thread. I would love to build my own, because I wanna save money, but i don't want to die.

and just for reference, how much could i build the ebay auction RPC for myself?

bump! back to the top for more input hopefully.

Most users want a simple system.

Alas, a multiple idler system is seldom simple.

The simplest multiple idler system would include fusible safety switches for each idler, and the first idler, possibly also the smallest, would have a starting means.

As manual switches would comprise the control system, there would be no interlocks for proper operation, and an overload in any idler would be diagnosed manually, probably requiring considerable time and knowledge of electrical components and systems.

After the first idler was started, additional idlers could be started on the three-phase which was supplied by the first idler.

The most complex multiple idler system would include magnetic motor starters for each idler, and again, the first idler would have a starting means, and again, additional idlers could be started from the first idler.

As semi-automatic switches would comprise the control system, there would be significant interlocks for proper operation, and an overload in any idler would be diagnosed automatically, requiring little time and nearly no knowledge of electrical components and systems.

Possibly the least cost RPC is a 5 HP idler with a Steveco 90-66 potential relay for automatic starting.

Simply placing such an RPC across the line results in an automatic start of that idler.

These 5 HP RPCs may be added to within reasonable limits, and as each RPC has its own starting means there would be no requirement for enforcing a particular starting order or sequence.

At the end of the day, the simplest, most affordable, and possibly the most reliable approach is one RPC per tool, each sized to its related tool.

In many cases, the control system for each tool may be incorporated into the control system for its RPC, so that the RPC and the tool are controlled as one unified device.

ok then, so one RPC for each tool, sized to its appropriate HP needs.

so tell me, how big of an RPC do i need for this 10 hp lathe?

i don't plan to ever need all 10 HP, but it sure would suck to have an occasion where i needed and didn't have access to it.

Thanks!

For a 10 HP lathe with a clutch, I would probably construct a 15 HP RPC.

If no clutch, then I might construct a 20 HP RPC.

ok cool, so in real hard numbers, how much $$$ can i make a 15 hp RPC for. What will it really cost me if i have to buy all the parts new...

and can a complete electrical tard put this thing together?

Carwash,

Peter has given you good information on the size and I agree a well built 15 hp is appropriate. I have see a 10 hp tried on a 10 hp Monarch and it will start the lathe by dimming the house lights. A 15 would be much better.

Look at a map and see how far you are from me. I live in Kingsport, Tn and currently have a 7.5 hp RPC under construction and plan to build another 7.5 and a 10 before Sept 15 of this year. If you are close enough to drop by then I would be glad to show you what it takes and I do have a Heavy duty 10 hp plan with is actually a 15 hp RPC built with a 10 hp idler. The plan can be changed in 10 minutes to make it a true 15 hp. This is the largest size I use my design for as it just costs too much to build them in larger sizes.

To use all new parts is cost prohibitive. You will need to get the more costly components as "good used" or "new old stock". Just try looking for a new Hoffman NEMA 12 electrical enclosure 16 x 20 x 7 or 16 x 20 x 8. There are other brands you can get a little cheaper.

Bruce Norton
Kingsport, Tn

"To use all new parts is cost prohibitive. You will need to get the more costly components as 'good used' or 'new old stock'. Just try looking for a new Hoffman NEMA 12 electrical enclosure 16 x 20 x 7 or 16 x 20 x 8. There are other brands you can get a little cheaper."

I always try for NOS or "good used" caps from Burden Surplus Center.

Sometimes, Burden also has NEMA enclosures of a reasonable size, but not often.

Hoffman makes pull-boxes of every conceivable size, and these are even available without pre-punched knock-outs, which I far prefer.

HF makes an affordable, and quite usable knockout punch set in every "trade size" from 1/2" to 1-1/4", inclusive, and I punch my conduit knock-outs at the time of installation.